Conventionally, a twin-screw extruding kneader is widely known as a device for producing a paste-like electrode mixture used for a battery such as a lithium-ion secondary battery.
JP-A 2005-222772 discloses a twin-screw extruding kneader having a kneading part for kneading a paste with a solid content higher than a final solid content, and a diluting part for adjusting the solid content of the paste kneaded in the kneading part to the final solid content.
The twin-screw extruding kneader disclosed in JP-A 2005-222772 can apply high shearing force to the paste in the kneading part to suitably reduce viscosity thereof, thus enabling to adjust the viscosity of the finally produced paste (electrode mixture) to a value suitable for the application of the paste to a current collector.
However, in the twin-screw extruding kneader disclosed in JP-A 2005-222772, a solvent is added to the paste to knead the paste in the diluting part as in the kneading part in order to adjust the solid content of the paste to the final solid content. As a result, in the diluting part only for adjusting the solid content, the viscosity of the paste may vary, which makes it difficult to adjust the viscosity of the finally produced paste (electrode mixture) to a desired value.